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Lei C, Dang Z, Zhu M, Zhang M, Wang H, Chen Y, Zhang H. Identification of the ERF gene family of Mangifera indica and the defense response of MiERF4 to Xanthomonas campestris pv. mangiferaeindicae. Gene 2024; 912:148382. [PMID: 38493974 DOI: 10.1016/j.gene.2024.148382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/03/2024] [Accepted: 03/14/2024] [Indexed: 03/19/2024]
Abstract
An important regulatory role for ethylene-responsive transcription factors (ERFs) is in plant growth and development, stress response, and hormone signaling. However, AP2/ERF family genes in mango have not been systematically studied. In this study, a total of 113 AP2/ERF family genes were identified from the mango genome and phylogenetically classified into five subfamilies: AP2 (28 genes), DREB (42 genes), ERF (33 genes), RAV (6 genes), and Soloist (4 genes). Of these, the ERF family, in conjunction with Arabidopsis and rice, forms a phylogenetic tree divided into seven groups, five of which have MiERF members. Analysis of gene structure and cis-elements showed that each MiERF gene contains only one AP2 structural domain, and that MiERF genes contain a large number of cis-elements associated with hormone signaling and stress response. Collinearity tests revealed a high degree of homology between MiERFs and CsERFs. Tissue-specific and stress-responsive expression profiling revealed that MiERF genes are primarily involved in the regulation of reproductive growth and are differentially and positively expressed in response to external hormones and pathogenic bacteria. Physiological results from a gain-of-function analysis of MiERF4 transiently overexpressed in tobacco and mango showed that transient expression of MiERF4 resulted in decreased colony count and callose deposition, as well as varying degrees of response to hormonal signals such as ETH, JA, and SA. Thus, MiERF4 may be involved in the JA/ETH signaling pathway to enhance plant defense against pathogenic bacteria. This study provides a basis for further research on the function and regulation of MiERF genes and lays a foundation for the selection of disease-resistant genes in mango.
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Affiliation(s)
- Chen Lei
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, China; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Zhiguo Dang
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Min Zhu
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Sanya Research Institute of Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China
| | - Mengting Zhang
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Huiliang Wang
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Yeyuan Chen
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Sanya Research Institute of Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China.
| | - He Zhang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, China; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
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Ramnarine SDB, Ali O, Jayaraman J, Ramsubhag A. Early transcriptional changes of heavy metal resistance and multiple efflux genes in Xanthomonas campestris pv. campestris under copper and heavy metal ion stress. BMC Microbiol 2024; 24:81. [PMID: 38461228 PMCID: PMC10924375 DOI: 10.1186/s12866-024-03206-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 01/28/2024] [Indexed: 03/11/2024] Open
Abstract
BACKGROUND Copper-induced gene expression in Xanthomonas campestris pv. campestris (Xcc) is typically evaluated using targeted approaches involving qPCR. The global response to copper stress in Xcc and resistance to metal induced damage is not well understood. However, homologs of heavy metal efflux genes from the related Stenotrophomonas genus are found in Xanthomonas which suggests that metal related efflux may also be present. METHODS AND RESULTS Gene expression in Xcc strain BrA1 exposed to 0.8 mM CuSO4.5H2O for 15 minutes was captured using RNA-seq analysis. Changes in expression was noted for genes related to general stress responses and oxidoreductases, biofilm formation, protein folding chaperones, heat-shock proteins, membrane lipid profile, multiple drug and efflux (MDR) transporters, and DNA repair were documented. At this timepoint only the cohL (copper homeostasis/tolerance) gene was upregulated as well as a chromosomal czcCBA efflux operon. An additional screen up to 4 hrs using qPCR was conducted using a wider range of heavy metals. Target genes included a cop-containing heavy metal resistance island and putative metal efflux genes. Several efflux pumps, including a copper resistance associated homolog from S. maltophilia, were upregulated under toxic copper stress. However, these pumps were also upregulated in response to other toxic heavy metals. Additionally, the temporal expression of the coh and cop operons was also observed, demonstrating co-expression of tolerance responses and later activation of part of the cop operon. CONCLUSIONS Overall, initial transcriptional responses focused on combating oxidative stress, mitigating protein damage and potentially increasing resistance to heavy metals and other biocides. A putative copper responsive efflux gene and others which might play a role in broader heavy metal resistance were also identified. Furthermore, the expression patterns of the cop operon in conjunction with other copper responsive genes allowed for a better understanding of the fate of copper ions in Xanthomonas. This work provides useful evidence for further evaluating MDR and other efflux pumps in metal-specific homeostasis and tolerance phenotypes in the Xanthomonas genus. Furthermore, non-canonical copper tolerance and resistance efflux pumps were potentially identified. These findings have implications for interpreting MIC differences among strains with homologous copLAB resistance genes, understanding survival under copper stress, and resistance in disease management.
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Affiliation(s)
- Stephen D B Ramnarine
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Omar Ali
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Jayaraj Jayaraman
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Adesh Ramsubhag
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I.
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Xu G, Ma J, Fang Q, Peng Q, Jiao X, Hu W, Zhao Q, Kong Y, Liu F, Shi X, Tang DJ, Tang JL, Ming Z. Structural insights into Xanthomonas campestris pv. campestris NAD + biosynthesis via the NAM salvage pathway. Commun Biol 2024; 7:255. [PMID: 38429435 PMCID: PMC10907753 DOI: 10.1038/s42003-024-05921-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/15/2024] [Indexed: 03/03/2024] Open
Abstract
Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) via the nicotinamide (NAM) salvage pathway. While the structural biochemistry of eukaryote NAMPT has been well studied, the catalysis mechanism of prokaryote NAMPT at the molecular level remains largely unclear. Here, we demonstrated the NAMPT-mediated salvage pathway is functional in the Gram-negative phytopathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) for the synthesis of NAD+, and the enzyme activity of NAMPT in this bacterium is significantly higher than that of human NAMPT in vitro. Our structural analyses of Xcc NAMPT, both in isolation and in complex with either the substrate NAM or the product nicotinamide mononucleotide (NMN), uncovered significant details of substrate recognition. Specifically, we revealed the presence of a NAM binding tunnel that connects the active site, and this tunnel is essential for both catalysis and inhibitor binding. We further demonstrated that NAM binding in the tunnel has a positive cooperative effect with NAM binding in the catalytic site. Additionally, we discovered that phosphorylation of the His residue at position 229 enhances the substrate binding affinity of Xcc NAMPT and is important for its catalytic activity. This work reveals the importance of NAMPT in bacterial NAD+ synthesis and provides insights into the substrate recognition and the catalytic mechanism of bacterial type II phosphoribosyltransferases.
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Affiliation(s)
- Guolyu Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Jinxue Ma
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Qi Fang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Qiong Peng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Xi Jiao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Wei Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Qiaoqiao Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Yanqiong Kong
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Fenmei Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Xueqi Shi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Dong-Jie Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China.
| | - Zhenhua Ming
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530004, P. R. China.
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Dey R, Chatterji BP. Sources and methods of manufacturing xanthan by fermentation of various carbon sources. Biotechnol Prog 2023; 39:e3379. [PMID: 37523474 DOI: 10.1002/btpr.3379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/04/2023] [Accepted: 07/12/2023] [Indexed: 08/02/2023]
Abstract
Xanthan gum, an anionic polysaccharide with an exceptionally high molecular weight, is produced by the bacterium Xanthomonas sp. It is a versatile compound that has been utilized in various industries for decades. Xanthan gum was the second exopolysaccharide to be commercially produced, following dextran. In 1969, the US Food and Drug Administration (FDA) approved xanthan gum for use in the food and pharmaceutical industries. The food industry values xanthan gum for its exceptional rheological properties, which make it a popular thickening agent in many products. Meanwhile, the cosmetics industry capitalizes on xanthan gum's ability to form stable emulsions. The industrial production process of xanthan gum involves fermenting Xanthomonas in a medium that contains glucose, sucrose, starch, etc. as a substrate and other necessary nutrients to facilitate growth. This is achieved through batch fermentation under optimal conditions. However, the increasing costs of glucose in recent years have made the production of xanthan economically unviable. Therefore, many researchers have investigated alternative, cost-effective substrates for xanthan production, using various modified and unmodified raw materials. The objective of this analysis is to investigate how utilizing different raw materials can improve the cost-efficient production of xanthan gum.
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Affiliation(s)
- Rahul Dey
- Department of Biotechnology, Assam down town University, Guwahati, India
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Chen XY, Hu SS, Xu XC, Tang JL, Tang DJ. RNase D Is Involved in 5S rRNA Degradation and Exopolysaccharide Production in Xanthomonas campestris pv. campestris. Phytopathology 2023; 113:1822-1832. [PMID: 37160665 DOI: 10.1094/phyto-09-22-0327-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Ribonucleases (RNases) play critical roles in RNA metabolism and are collectively essential for cell viability. However, most knowledge about bacterial RNases comes from the studies on Escherichia coli; very little is known about the RNases in plant pathogens. The crucifer black rot pathogen Xanthomonas campestris pv. campestris (Xcc) encodes 15 RNases, but none of them has been functionally characterized. Here, we report the physiological function of the exoribonuclease RNase D in Xcc and provide evidence demonstrating that the Xcc RNase D is involved in 5S rRNA degradation and exopolysaccharide (EPS) production. Our work shows that the growth and virulence of Xcc were not affected by deletion of RNase D but were severely attenuated by RNase D overexpression. However, deletion of RNase D in Xcc resulted in a significant reduction in EPS production. In addition, either deletion or overexpression of RNase D in Xcc did not influence the tRNAs tested, inconsistent with the finding in E. coli that the primary function of RNase D is to participate in tRNA maturation and its overexpression degrades tRNAs. More importantly, deletion, overexpression, and in vitro enzymatic analyses revealed that the Xcc RNase D degrades 5S rRNA but not 16S and 23S rRNAs that share an operon with 5S rRNA. Our results suggest that Xcc employs RNase D to realize specific modulation of the cellular 5S rRNA content after transcription and maturation whenever necessary. The finding expands our knowledge about the function of RNase D in bacteria.
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Affiliation(s)
- Xin-Yi Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Shan-Shan Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Xiao-Can Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Dong-Jie Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
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Li JB, Xiong LT, Lu YR, Zhang YQ, Xu XL, Wang HH, Deng X, Hu XH, Cui ZN. Novel pyrimidin-4-one derivatives as potential T3SS inhibitors against Xanthomonas campestris pv. campestris. Pest Manag Sci 2023; 79:3666-3675. [PMID: 37184259 DOI: 10.1002/ps.7545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/16/2023]
Abstract
BACKGROUND Cruciferous black rot is caused by Xanthomonas campestris pv. campestris (Xcc) infection and is a widespread disease worldwide. Excessive and repeated use of bactericide is an important cause of the development of bacterial resistance. It is imperative to take new approaches to screening compounds that target virulence factors rather than kill bacterial pathogens. The type III secretion system (T3SS) invades a variety of cells by transporting virulence effector factors into the cytoplasm and is an attractive antitoxic target. Toward the search of new T3SS inhibitors, an alternative series of novel pyrimidin-4-one derivatives were designed and synthesized and assessed for their effect in blocking the virulence. RESULTS All of the target compounds were characterized by proton (1 H) nuclear magnetic resonance (NMR), carbon-13 (13 C) NMR, fluorine-19 (19 F) NMR and high-resolution mass spectrometry (HRMS). All compounds were evaluated using high-throughput screening systems against Xcc. The results of the biological activity test revealed that the compound SPF-9 could highly inhibit the activity of xopN gene promoter and the hypersensitivity (HR) of tobacco without affecting bacterial growth. Moreover, messenger RNA (mRNA) level measurements showed that compound SPF-9 inhibited the expression of some representative genes (hrp/hrc genes). Compound SPF-9 weakened the pathogenicity of Xcc to Raphanus sativus L. CONCLUSION Compound SPF-9 has good potential for further development as a novel T3SS inhibitor against Xcc. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Jia-Bao Li
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Lan-Tu Xiong
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Yan-Rong Lu
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Yu-Qing Zhang
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Xiao-Li Xu
- Instrumental Analysis and Research Center, South China Agricultural University, Guangzhou, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Xu-Hong Hu
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, China
| | - Zi-Ning Cui
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, China
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Kotsaridis K, Michalopoulou VA, Tsakiri D, Kotsifaki D, Kefala A, Kountourakis N, Celie PHN, Kokkinidis M, Sarris PF. The functional and structural characterization of Xanthomonas campestris pv. campestris core effector XopP revealed a new kinase activity. Plant J 2023; 116:100-111. [PMID: 37344990 DOI: 10.1111/tpj.16362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 06/23/2023]
Abstract
Exo70B1 is a protein subunit of the exocyst complex with a crucial role in a variety of cell mechanisms, including immune responses against pathogens. The calcium-dependent kinase 5 (CPK5) of Arabidopsis thaliana (hereafter Arabidopsis), phosphorylates AtExo70B1 upon functional disruption. We previously reported that, the Xanthomonas campestris pv. campestris effector XopP compromises AtExo70B1, while bypassing the host's hypersensitive response, in a way that is still unclear. Herein we designed an experimental approach, which includes biophysical, biochemical, and molecular assays and is based on structural and functional predictions, utilizing AplhaFold and DALI online servers, respectively, in order to characterize the in vivo XccXopP function. The interaction between AtExo70B1 and XccXopP was found very stable in high temperatures, while AtExo70B1 appeared to be phosphorylated at XccXopP-expressing transgenic Arabidopsis. XccXopP revealed similarities with known mammalian kinases and phosphorylated AtExo70B1 at Ser107, Ser111, Ser248, Thr309, and Thr364. Moreover, XccXopP protected AtExo70B1 from AtCPK5 phosphorylation. Together these findings show that XccXopP is an effector, which not only functions as a novel serine/threonine kinase upon its host target AtExo70B1 but also protects the latter from the innate AtCPK5 phosphorylation, in order to bypass the host's immune responses. Data are available via ProteomeXchange with the identifier PXD041405.
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Affiliation(s)
- Konstantinos Kotsaridis
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Vassiliki A Michalopoulou
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Dimitra Tsakiri
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
| | - Dina Kotsifaki
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
| | - Aikaterini Kefala
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Nikos Kountourakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Patrick H N Celie
- Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Michael Kokkinidis
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Panagiotis F Sarris
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
- Biosciences, University of Exeter, Exeter, UK
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Ortmann S, Marx J, Lampe C, Handrick V, Ehnert TM, Zinecker S, Reimers M, Bonas U, Erickson JL. A conserved microtubule-binding region in Xanthomonas XopL is indispensable for induced plant cell death reactions. PLoS Pathog 2023; 19:e1011263. [PMID: 37578981 PMCID: PMC10449215 DOI: 10.1371/journal.ppat.1011263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 08/24/2023] [Accepted: 07/17/2023] [Indexed: 08/16/2023] Open
Abstract
Pathogenic Xanthomonas bacteria cause disease on more than 400 plant species. These Gram-negative bacteria utilize the type III secretion system to inject type III effector proteins (T3Es) directly into the plant cell cytosol where they can manipulate plant pathways to promote virulence. The host range of a given Xanthomonas species is limited, and T3E repertoires are specialized during interactions with specific plant species. Some effectors, however, are retained across most strains, such as Xanthomonas Outer Protein L (XopL). As an 'ancestral' effector, XopL contributes to the virulence of multiple xanthomonads, infecting diverse plant species. XopL homologs harbor a combination of a leucine-rich-repeat (LRR) domain and an XL-box which has E3 ligase activity. Despite similar domain structure there is evidence to suggest that XopL function has diverged, exemplified by the finding that XopLs expressed in plants often display bacterial species-dependent differences in their sub-cellular localization and plant cell death reactions. We found that XopL from X. euvesicatoria (XopLXe) directly associates with plant microtubules (MTs) and causes strong cell death in agroinfection assays in N. benthamiana. Localization of XopLXe homologs from three additional Xanthomonas species, of diverse infection strategy and plant host, revealed that the distantly related X. campestris pv. campestris harbors a XopL (XopLXcc) that fails to localize to MTs and to cause plant cell death. Comparative sequence analyses of MT-binding XopLs and XopLXcc identified a proline-rich-region (PRR)/α-helical region important for MT localization. Functional analyses of XopLXe truncations and amino acid exchanges within the PRR suggest that MT-localized XopL activity is required for plant cell death reactions. This study exemplifies how the study of a T3E within the context of a genus rather than a single species can shed light on how effector localization is linked to biochemical activity.
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Affiliation(s)
- Simon Ortmann
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
| | - Jolina Marx
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Christina Lampe
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Vinzenz Handrick
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
| | - Tim-Martin Ehnert
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
| | - Sarah Zinecker
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Matthias Reimers
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Ulla Bonas
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Jessica Lee Erickson
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Department of Biochemistry of Plant Interactions, Leibniz Institute for Plant Biochemistry, Halle, Germany
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Yu YH, Chen C, Ma JR, Zhang YY, Yan MF, Zhang WB, Hu Z, Wang HH, Ma JC. The FabA-FabB Pathway Is Not Essential for Unsaturated Fatty Acid Synthesis but Modulates Diffusible Signal Factor Synthesis in Xanthomonas campestris pv. campestris. Mol Plant Microbe Interact 2023; 36:119-130. [PMID: 36515967 DOI: 10.1094/mpmi-09-22-0182-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Most bacteria use type II fatty acid synthesis (FAS) systems for synthesizing fatty acids, of which the conserved FabA-FabB pathway is considered to be crucial for unsaturated fatty acid (UFA) synthesis in gram-negative bacteria. Xanthomonas campestris pv. campestris, the phytopathogen of black rot disease in crucifers, produces higher quantities of UFAs under low-temperature conditions for increasing membrane fluidity. The fabA and fabB genes were identified in the X. campestris pv. campestris genome by BLAST analysis; however, the growth of the X. campestris pv. campestris fabA and fabB deletion mutants was comparable to that of the wild-type strain in nutrient and minimal media. The X. campestris pv. campestris ΔfabA and ΔfabB strains produced large quantities of UFAs and, altogether, these results indicated that the FabA-FabB pathway is not essential for growth or UFA synthesis in X. campestris pv. campestris. We also observed that the expression of X. campestris pv. campestris fabA and fabB restored the growth of the temperature-sensitive Escherichia coli fabA and fabB mutants CL104 and CY242, respectively, under non-permissive conditions. The in-vitro assays demonstrated that the FabA and FabB proteins of X. campestris pv. campestris catalyzed FAS. Our study also demonstrated that the production of diffusible signal factor family signals that mediate quorum sensing was higher in the X. campestris pv. campestris ΔfabA and ΔfabB strains and greatly reduced in the complementary strains, which exhibited reduced swimming motility and attenuated host-plant pathogenicity. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Cheng Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jian-Rong Ma
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
| | - Yuan-Yin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Ming-Feng Yan
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
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10
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Wang B, Li K, Wu G, Xu Z, Hou R, Guo B, Zhao Y, Liu F. Sulforaphane, a secondary metabolite in crucifers, inhibits the oxidative stress adaptation and virulence of Xanthomonas by directly targeting OxyR. Mol Plant Pathol 2022; 23:1508-1523. [PMID: 35942507 PMCID: PMC9452769 DOI: 10.1111/mpp.13245] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 06/12/2022] [Accepted: 06/13/2022] [Indexed: 05/19/2023]
Abstract
Plant secondary metabolites perform numerous functions in the interactions between plants and pathogens. However, little is known about the precise mechanisms underlying their contribution to the direct inhibition of pathogen growth and virulence in planta. Here, we show that the secondary metabolite sulforaphane (SFN) in crucifers inhibits the growth, virulence, and ability of Xanthomonas species to adapt to oxidative stress, which is essential for the successful infection of host plants by phytopathogens. The transcription of oxidative stress detoxification-related genes (catalase [katA and katG] and alkylhydroperoxide-NADPH oxidoreductase subunit C [ahpC]) was substantially inhibited by SFN in Xanthomonas campestris pv. campestris (Xcc), and this phenomenon was most obvious in sax gene mutants sensitive to SFN. By performing microscale thermophoresis (MST) and electrophoretic mobility shift assay (EMSA), we observed that SFN directly bound to the virulence-related redox-sensing transcription factor OxyR and weakened the ability of OxyR to bind to the promoters of oxidative stress detoxification-related genes. Collectively, these results illustrate that SFN directly targets OxyR to inhibit the bacterial adaptation to oxidative stress, thereby decreasing bacterial virulence. Interestingly, this phenomenon occurs in multiple Xanthomonas species. This study provides novel insights into the molecular mechanisms by which SFN limits Xanthomonas adaptation to oxidative stress and virulence, and the findings will facilitate future studies on the use of SFN as a biopesticide to control Xanthomonas.
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Affiliation(s)
- Bo Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
| | - Kaihuai Li
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Guichun Wu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
| | - Zhizhou Xu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Rongxian Hou
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Baodian Guo
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and SafetyState Key Laboratory Cultivation Base of Ministry of Science and TechnologyNanjingChina
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Raffeiner M, Üstün S, Guerra T, Spinti D, Fitzner M, Sonnewald S, Baldermann S, Börnke F. The Xanthomonas type-III effector XopS stabilizes CaWRKY40a to regulate defense responses and stomatal immunity in pepper (Capsicum annuum). Plant Cell 2022; 34:1684-1708. [PMID: 35134217 PMCID: PMC9048924 DOI: 10.1093/plcell/koac032] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/20/2022] [Indexed: 05/26/2023]
Abstract
As a critical part of plant immunity, cells that are attacked by pathogens undergo rapid transcriptional reprogramming to minimize virulence. Many bacterial phytopathogens use type III effector (T3E) proteins to interfere with plant defense responses, including this transcriptional reprogramming. Here, we show that Xanthomonas outer protein S (XopS), a T3E of Xanthomonas campestris pv. vesicatoria (Xcv), interacts with and inhibits proteasomal degradation of WRKY40, a transcriptional regulator of defense gene expression. Virus-induced gene silencing of WRKY40 in pepper (Capsicum annuum) enhanced plant tolerance to Xcv infection, indicating that WRKY40 represses immunity. Stabilization of WRKY40 by XopS reduces the expression of its targets, which include salicylic acid-responsive genes and the jasmonic acid signaling repressor JAZ8. Xcv bacteria lacking XopS display significantly reduced virulence when surface inoculated onto susceptible pepper leaves. XopS delivery by Xcv, as well as ectopic expression of XopS in Arabidopsis thaliana or Nicotiana benthamiana, prevented stomatal closure in response to bacteria and biotic elicitors. Silencing WRKY40 in pepper or N. benthamiana abolished XopS's ability to prevent stomatal closure. This suggests that XopS interferes with both preinvasion and apoplastic defense by manipulating WRKY40 stability and downstream gene expression, eventually altering phytohormone crosstalk to promote pathogen proliferation.
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Affiliation(s)
- Margot Raffeiner
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
| | | | - Tiziana Guerra
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
| | - Daniela Spinti
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam 14476, Germany
| | - Maria Fitzner
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
| | - Sophia Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-Universität, Erlangen 91058, Germany
| | - Susanne Baldermann
- Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren 14979, Germany
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal 14558, Germany
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Chen YC, Hu Z, Zhang WB, Yin Y, Zhong CY, Mo WY, Yu YH, Ma JC, Wang HH. HetI-Like Phosphopantetheinyl Transferase Posttranslationally Modifies Acyl Carrier Proteins in Xanthomonas spp. Mol Plant Microbe Interact 2022; 35:323-335. [PMID: 35286156 DOI: 10.1094/mpmi-10-21-0249-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In Xanthomonas spp., the biosynthesis of the yellow pigment xanthomonadin and fatty acids originates in the type II polyketide synthase (PKS II) and fatty acid synthase (FAS) pathways, respectively. The acyl carrier protein (ACP) is the central component of PKS II and FAS and requires posttranslational phosphopantetheinylation to initiate these pathways. In this study, for the first time, we demonstrate that the posttranslational modification of ACPs in X. campestris pv. campestris is performed by an essential 4'-phosphopantetheinyl transferase (PPTase), XcHetI (encoded by Xc_4132). X. campestris pv. campestris strain XchetI could not be deleted from the X. campestris pv. campestris genome unless another PPTase-encoding gene such as Escherichia coli acpS or Pseudomonas aeruginosa pcpS was present. Compared with wild-type strain X. campestris pv. campestris 8004 and mutant XchetI::PapcpS, strain XchetI::EcacpS failed to generate xanthomonadin pigments and displayed reduced pathogenicity for the host plant, Brassica oleracea. Further experiments showed that the expression of XchetI restored the growth of E. coli acpS mutant HT253 and, when a plasmid bearing XchetI was introduced into P. aeruginosa, pcpS, which encodes the sole PPTase in P. aeruginosa, could be deleted. In in vitro enzymatic assays, XcHetI catalyzed the transformation of 4'-phosphopantetheine from coenzyme A to two X. campestris pv. campestris apo-acyl carrier proteins, XcAcpP and XcAcpC. All of these findings indicate that XcHetI is a surfactin PPTase-like PPTase with a broad substrate preference. Moreover, the HetI-like PPTase is ubiquitously conserved in Xanthomonas spp., making it a potential new drug target for the prevention of plant diseases caused by Xanthomonas.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Yi-Cai Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yu Yin
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Can-Yao Zhong
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wan-Ying Mo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
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13
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Su Q, Wang X, Leng M, Qi Y, Pang F, Tang J, Lu G. A HU-like protein is required for full virulence in Xanthomonas campestris pv. campestris. Mol Plant Pathol 2021; 22:1574-1586. [PMID: 34424610 PMCID: PMC8578834 DOI: 10.1111/mpp.13128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/26/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Bacteria harbour several abundant small DNA-binding proteins known as nucleoid-associated proteins (NAPs) that contribute to the structure of the bacterial nucleoid as well as to gene regulation. Although the function of NAPs as global transcriptional regulators has been comprehensively studied in the model organism Escherichia coli, their regulatory functions in other bacteria remain relatively poorly understood. Xanthomonas campestris pv. campestris (Xcc) is a gram-negative bacterium that causes black rot disease in almost all members of the crucifer family. In previous work, we demonstrated that a Fis homologue protein, which we named Fis-like protein (Flp), contributes to the regulation of virulence, type III secretion, and a series of other phenotypes in Xcc. Here we have examined the role of XC_1355, which is predicted to encode a DNA-binding protein belonging to the HU family herein named HU-like protein (Hlp). We show that mutation of XC_1355 in Xcc reduces the virulence, extracellular polysaccharide production, and cell motility, but has no effect on the production of extracellular enzymes and induction of the hypersensitive response. These data together with transcriptome analysis indicate that hlp is a previously uncharacterized gene involved in virulence that has partially overlapping and complementary functions with flp in Xcc, although the two regulators have opposite effects on the expression of genes involved in type III secretion. The findings add to our understanding of the complex regulatory pathways that act to regulate virulence in Xcc.
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Affiliation(s)
- Qian Su
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Xin‐Xin Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Ming Leng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Yan‐Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Fu‐Yuan Pang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
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14
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Sun H, Zhu X, Li C, Ma Z, Han X, Luo Y, Yang L, Yu J, Miao Y. Xanthomonas effector XopR hijacks host actin cytoskeleton via complex coacervation. Nat Commun 2021; 12:4064. [PMID: 34210966 PMCID: PMC8249405 DOI: 10.1038/s41467-021-24375-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 06/11/2021] [Indexed: 01/09/2023] Open
Abstract
The intrinsically disordered region (IDR) is a preserved signature of phytobacterial type III effectors (T3Es). The T3E IDR is thought to mediate unfolding during translocation into the host cell and to avoid host defense by sequence diversification. Here, we demonstrate a mechanism of host subversion via the T3E IDR. We report that the Xanthomonas campestris T3E XopR undergoes liquid-liquid phase separation (LLPS) via multivalent IDR-mediated interactions that hijack the Arabidopsis actin cytoskeleton. XopR is gradually translocated into host cells during infection and forms a macromolecular complex with actin-binding proteins at the cell cortex. By tuning the physical-chemical properties of XopR-complex coacervates, XopR progressively manipulates multiple steps of actin assembly, including formin-mediated nucleation, crosslinking of F-actin, and actin depolymerization, which occurs through competition for actin-depolymerizing factor and depends on constituent stoichiometry. Our findings unravel a sophisticated strategy in which bacterial T3E subverts the host actin cytoskeleton via protein complex coacervation.
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Affiliation(s)
- He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xinlu Zhu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Chuanxi Li
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yuanyuan Luo
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jing Yu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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15
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Lin Y, Liao YY, Huang RX, Li AZ, An SQ, Tang JL, Tang DJ. Extracellular Amylase Is Required for Full Virulence and Regulated by the Global Posttranscriptional Regulator RsmA in Xanthomonas campestris Pathovar campestris. Phytopathology 2021; 111:1104-1113. [PMID: 33245253 DOI: 10.1094/phyto-08-20-0372-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As with many phytopathogenic bacteria, the virulence of Xanthomonas campestris pv. campestris, the causal agent of black rot disease in cruciferous plants, relies on secretion of a suite of extracellular enzymes that includes cellulase (endoglucanase), pectinase, protease, and amylase. Although the role in virulence of a number of these enzymes has been assessed, the contribution of amylase to X. campestris pv. campestris virulence has yet to be established. In this work, we investigated both the role of extracellular amylase in X. campestris pv. campestris virulence and the control of its expression. Deletion of XC3487 (here renamed amyAXcc), a putative amylase-encoding gene from the genome of X. campestris pv. campestris strain 8004, resulted in a complete loss of extracellular amylase activity and significant reduction in virulence. The extracellular amylase activity and virulence of the amyAXcc mutant could be restored to the wild-type level by expressing amyAXcc in trans. These results demonstrated that amyAXcc is responsible for the extracellular amylase activity of X. campestris pv. campestris and indicated that extracellular amylase plays an important role in X. campestris pv. campestris virulence. We also found that the expression of amyAXcc is strongly induced by starch and requires activation by the global posttranscriptional regulator RsmA. RsmA binds specifically to the 5'-untranslated region of amyAXcc transcripts, suggesting that RsmA regulates amyAXcc directly at the posttranscriptional level. Unexpectedly, in addition to posttranscriptional regulation, the use of a transcriptional reporter demonstrated that RsmA also regulates amyAXcc expression at the transcriptional level, possibly by an indirect mechanism.
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Affiliation(s)
- Yan Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Yong-Yan Liao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Ru-Xia Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Ai-Zhou Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Shi-Qi An
- National Biofilms Innovation Centre, Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Dong-Jie Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
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Chen L, Wang M, Feng Y, Xu X, Luo X, Zhang Z. Production of bioelectricity may play an important role for the survival of Xanthomonas campestris pv. campestris (Xcc) under anaerobic conditions. Sci Total Environ 2021; 768:144335. [PMID: 33736299 DOI: 10.1016/j.scitotenv.2020.144335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 11/18/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
The plant pathogen Xanthomonas is commonly found in biocontaminated bioreactors; however, few studies have evaluated the growth and impacts of this microorganism on bioreactors. In this study, we examined the characteristics of Xanthomonas campestris pv. campestris (Xcc). Our results showed that Xcc could reduce metal Fe (III) and decolorise methyl orange in vitro. Moreover, I-t and cyclic voltammetry curves showed that Xcc could generate bioelectricity and had two extracellular electron transfer pathways, similar to that of Shewanella. Based on the spectral analysis of intact cells and scanning electron microscopy analysis, one pathway was speculated to involve cytochrome C by direct contact with the pili or cell surface. The other pathway may involve indirect mediators, such as redox substrates, among extracellular polymeric substances. For the direct extracellular electron transfer process, the charge transfer coefficient α, electron number n, and the electron transfer rate constant ks were determined to be 0.49, 2.6, and 2.2 × 10-3 s-1, respectively. In the indirect extracellular electron transfer processes, the values of α, n, and ks were 0.52, 4, and 1.21 s-1, respectively. Of these two transfer methods, indirect electron transfer is dominant and faster than direct electron transfer. Moreover, after mutation of the dsbD gene, which is important for indirect electron transfer, the electrochemical parameters α, n, and ks decreased. Our findings reveal a new anaerobic mechanism mediating the survival of Xcc during wastewater treatment, and may help develop new strategies for preventing Xcc growth during wastewater treatment.
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Affiliation(s)
- Lei Chen
- School of Life Science, Qufu Normal University, Qufu 273165, China
| | - Mingpeng Wang
- School of Life Science, Qufu Normal University, Qufu 273165, China.
| | - Yujie Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xiaoyu Xu
- School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Xiaobo Luo
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Zhaojie Zhang
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
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Gan YL, Yang LY, Yang LC, Li WL, Liang XL, Jiang W, Jiang GF, Hang XH, Yang M, Tang JL, Jiang BL. The C-terminal domain of the type III secretion chaperone HpaB contributes to dissociation of chaperone-effector complex in Xanthomonas campestris pv. campestris. PLoS One 2021; 16:e0246033. [PMID: 33507993 PMCID: PMC7842900 DOI: 10.1371/journal.pone.0246033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/12/2021] [Indexed: 12/01/2022] Open
Abstract
Many animal and plant pathogenic bacteria employ a type three secretion system (T3SS) to deliver type three effector proteins (T3Es) into host cells. Efficient secretion of many T3Es in the plant pathogen Xanthomonas campestris pv. campestris (Xcc) relies on the global chaperone HpaB. However, how the domain of HpaB itself affects effector translocation/secretion is poorly understood. Here, we used genetic and biochemical approaches to identify a novel domain at the C-terminal end of HpaB (amino acid residues 137-160) that contributes to virulence and hypersensitive response (HR). Both in vitro secretion assay and in planta translocation assay showed that the secretion and translocation of T3E proteins depend on the C-terminal region of HpaB. Deletion of the C-terminal region of HpaB did not affect binding to T3Es, self-association or interaction with T3SS components. However, the deletion of C-terminal region sharply reduced the mounts of free T3Es liberated from the complex of HpaB with the T3Es, a reaction catalyzed in an ATP-dependent manner by the T3SS-associated ATPase HrcN. Our findings demonstrate the C-terminal domain of HpaB contributes to disassembly of chaperone-effector complex and reveal a potential molecular mechanism underpinning the involvement of HpaB in secretion of T3Es in Xcc.
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Affiliation(s)
- Yong-Liang Gan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Li-Yan Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Li-Chao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Wan-Lian Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xue-Lian Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Wei Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | | | - Xiao-Hong Hang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Mei Yang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Bo-Le Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
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18
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Tinte MM, Steenkamp PA, Piater LA, Dubery IA. Lipopolysaccharide perception in Arabidopsis thaliana: Diverse LPS chemotypes from Burkholderia cepacia, Pseudomonas syringae and Xanthomonas campestris trigger differential defence-related perturbations in the metabolome. Plant Physiol Biochem 2020; 156:267-277. [PMID: 32987257 DOI: 10.1016/j.plaphy.2020.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/04/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
Lipopolysaccharides (LPSs) are microbe-associated molecular pattern molecules (MAMPs) from Gram-negative bacterial pathogens that potentially contain three different MAMPs (the O-polysaccharide chain, the oligosaccharide core and lipid A). LPSs was purified from Burkholderia cepacia, Pseudomonas syringae and Xanthomonas campestris and electrophoretically profiled. Outcomes of the interactions of the three different LPS chemotypes with Arabidopsis thaliana, as reflected in the induced defence metabolites, profiled at 12 h and 24 h post elicitation, were investigated. Plants were pressure-infiltrated with LPS solutions and methanol-based extractions at different time points were performed for untargeted metabolomics using ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Multivariate data modelling and chemometric analysis were applied to generate interpretable biochemical information from the multidimensional data sets. The three LPSs triggered differential metabolome changes in the plants as apparent from chromatographically distinct MS chromatograms. Unsupervised and supervised multivariate data models exhibited time- and treatment-related variations, and revealed discriminating metabolite variables. Heat map models comparatively displayed the up-regulated pathways affecting the metabolomes and Venn diagrams indicated up-regulated and shared metabolites among the three LPS treatments. The altered metabolomes reflect the up-regulation of metabolites from not only the glucosinolate pathway, but also from the shikimate-phenylpropanoid-flavonoid -, terpenoid - and indolic/alkaloid pathways, as well as oxygenated fatty acids. Distinct phytochemical profiles, especially at the earlier time point, suggest differences in the perception of the three LPS chemotypes, associated with the molecular patterns within the tripartite lipoglycans.
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Affiliation(s)
- Morena M Tinte
- Research Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa
| | - Paul A Steenkamp
- Research Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa
| | - Lizelle A Piater
- Research Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa
| | - Ian A Dubery
- Research Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa.
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19
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Tran TM, Ma Z, Triebl A, Nath S, Cheng Y, Gong BQ, Han X, Wang J, Li JF, Wenk MR, Torta F, Mayor S, Yang L, Miao Y. The bacterial quorum sensing signal DSF hijacks Arabidopsis thaliana sterol biosynthesis to suppress plant innate immunity. Life Sci Alliance 2020; 3:e202000720. [PMID: 32788227 PMCID: PMC7425213 DOI: 10.26508/lsa.202000720] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 07/26/2020] [Accepted: 07/30/2020] [Indexed: 01/04/2023] Open
Abstract
Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (cis-11-methyl-dodecenoic acid) produced by Xanthomonas campestris pv. campestris can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in Arabidopsis thaliana, mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of Arabidopsis, with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.
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Affiliation(s)
- Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Alexander Triebl
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sangeeta Nath
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore, India
| | - Yingying Cheng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ben-Qiang Gong
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Junqi Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Jian-Feng Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Markus R Wenk
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Federico Torta
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Satyajit Mayor
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
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20
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González‐Fuente M, Carrère S, Monachello D, Marsella BG, Cazalé A, Zischek C, Mitra RM, Rezé N, Cottret L, Mukhtar MS, Lurin C, Noël LD, Peeters N. EffectorK, a comprehensive resource to mine for Ralstonia, Xanthomonas, and other published effector interactors in the Arabidopsis proteome. Mol Plant Pathol 2020; 21:1257-1270. [PMID: 33245626 PMCID: PMC7488465 DOI: 10.1111/mpp.12965] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 05/16/2023]
Abstract
Pathogens deploy effector proteins that interact with host proteins to manipulate the host physiology to the pathogen's own benefit. However, effectors can also be recognized by host immune proteins, leading to the activation of defence responses. Effectors are thus essential components in determining the outcome of plant-pathogen interactions. Despite major efforts to decipher effector functions, our current knowledge on effector biology is scattered and often limited. In this study, we conducted two systematic large-scale yeast two-hybrid screenings to detect interactions between Arabidopsis thaliana proteins and effectors from two vascular bacterial pathogens: Ralstonia pseudosolanacearum and Xanthomonas campestris. We then constructed an interactomic network focused on Arabidopsis and effector proteins from a wide variety of bacterial, oomycete, fungal, and invertebrate pathogens. This network contains our experimental data and protein-protein interactions from 2,035 peer-reviewed publications (48,200 Arabidopsis-Arabidopsis and 1,300 Arabidopsis-effector protein interactions). Our results show that effectors from different species interact with both common and specific Arabidopsis interactors, suggesting dual roles as modulators of generic and adaptive host processes. Network analyses revealed that effector interactors, particularly "effector hubs" and bacterial core effector interactors, occupy important positions for network organization, as shown by their larger number of protein interactions and centrality. These interactomic data were incorporated in EffectorK, a new graph-oriented knowledge database that allows users to navigate the network, search for homology, or find possible paths between host and/or effector proteins. EffectorK is available at www.effectork.org and allows users to submit their own interactomic data.
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Affiliation(s)
- Manuel González‐Fuente
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
| | - Sébastien Carrère
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
| | - Dario Monachello
- Institut des Sciences des Plantes de Paris SaclayUEVEINRAECNRSUniversité Paris SudUniversité Paris‐SaclayGif‐sur‐YvetteFrance
- Université de ParisGif‐sur‐YvetteFrance
| | | | - Anne‐Claire Cazalé
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
| | - Claudine Zischek
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
| | - Raka M. Mitra
- Department of BiologyCarleton CollegeNorthfieldMNUSA
| | - Nathalie Rezé
- Institut des Sciences des Plantes de Paris SaclayUEVEINRAECNRSUniversité Paris SudUniversité Paris‐SaclayGif‐sur‐YvetteFrance
- Université de ParisGif‐sur‐YvetteFrance
| | - Ludovic Cottret
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
| | - M. Shahid Mukhtar
- Department of BiologyUniversity of Alabama at BirminghamBirminghamALUSA
| | - Claire Lurin
- Institut des Sciences des Plantes de Paris SaclayUEVEINRAECNRSUniversité Paris SudUniversité Paris‐SaclayGif‐sur‐YvetteFrance
- Université de ParisGif‐sur‐YvetteFrance
| | - Laurent D. Noël
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
| | - Nemo Peeters
- Laboratoire des Interactions Plantes Micro‐organismes, INRAECNRSUniversité de ToulouseCastanet‐TolosanFrance
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21
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Tran TM, Ma Z, Triebl A, Nath S, Cheng Y, Gong BQ, Han X, Wang J, Li JF, Wenk MR, Torta F, Mayor S, Yang L, Miao Y. The bacterial quorum sensing signal DSF hijacks Arabidopsis thaliana sterol biosynthesis to suppress plant innate immunity. Life Sci Alliance 2020. [PMID: 32788227 DOI: 10.1101/927731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (cis-11-methyl-dodecenoic acid) produced by Xanthomonas campestris pv. campestris can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in Arabidopsis thaliana, mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of Arabidopsis, with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.
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Affiliation(s)
- Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Alexander Triebl
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sangeeta Nath
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore, India
| | - Yingying Cheng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ben-Qiang Gong
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Junqi Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Jian-Feng Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Markus R Wenk
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Federico Torta
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Satyajit Mayor
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
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22
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Li K, Wu G, Liao Y, Zeng Q, Wang H, Liu F. RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris. Mol Plant Pathol 2020; 21:907-922. [PMID: 32281725 PMCID: PMC7280030 DOI: 10.1111/mpp.12938] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 05/08/2023]
Abstract
Homologous regulatory factors are widely present in bacteria, but whether homologous regulators synergistically or differentially regulate different biological functions remains mostly unknown. Here, we report that the homologous regulators RpoN1 and RpoN2 of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) play different regulatory roles with respect to virulence traits, flagellar biosynthesis, and basal metabolism. RpoN2 directly regulated Xcc fliC and fliQ to modulate flagellar synthesis in X. campestris, thus affecting the swimming motility of X. campestris. Mutation of rpoN2 resulted in reduced production of biofilms and extracellular polysaccharides in Xcc. These defects may together cause reduced virulence of the rpoN2 mutant against the host plant. Moreover, we demonstrated that RpoN1 could regulate branched-chain fatty acid production and modulate the synthesis of diffusible signal factor family quorum sensing signals. Although RpoN1 and RpoN2 are homologues, the regulatory roles and biological functions of these proteins were not interchangeable. Overall, our report provides new insights into the two different molecular roles that form the basis for the transcriptional specialization of RpoN homologues.
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Affiliation(s)
- Kaihuai Li
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Guichun Wu
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Quan Zeng
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew HavenCTUSA
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Fengquan Liu
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
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23
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Zhang H, Wei J, Qian W, Deng C. Analysis of HrpG regulons and HrpG-interacting proteins by ChIP-seq and affinity proteomics in Xanthomonas campestris. Mol Plant Pathol 2020; 21:388-400. [PMID: 31916392 PMCID: PMC7036363 DOI: 10.1111/mpp.12903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/06/2019] [Accepted: 11/27/2019] [Indexed: 06/02/2023]
Abstract
Gamma-proteobacteria Xanthomonas spp. cause at least 350 different plant diseases among important agricultural crops, which result in serious yield losses. Xanthomonas spp. rely mainly on the type III secretion system (T3SS) to infect their hosts and induce a hypersensitive response in nonhosts. HrpG, the master regulator of the T3SS, plays the dominant role in bacterial virulence. In this study, we used chromatin immunoprecipitation followed by sequencing (ChIP-seq) and tandem affinity purification (TAP) to systematically characterize the HrpG regulon and HrpG interacting proteins in vivo. We obtained 186 candidate HrpG downstream genes from the ChIP-seq analysis, which represented the genomic-wide regulon spectrum. A consensus HrpG-binding motif was obtained and three T3SS genes, hpa2, hrcU, and hrpE, were confirmed to be directly transcriptionally activated by HrpG in the inducing medium. A total of 273 putative HrpG interacting proteins were identified from the TAP data and the DNA-binding histone-like HU protein of Xanthomonas campestris pv. campestris (HUxcc ) was proved to be involved in bacterial virulence by increasing the complexity and intelligence of the bacterial signalling pathways in the T3SS.
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Affiliation(s)
- Hong‐Yu Zhang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Jin‐Wei Wei
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Wei Qian
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Chao‐Ying Deng
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
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24
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Han S, Shen D, Wang Y, Chou S, Gomelsky M, Gao Y, Qian G. A YajQ-LysR-like, cyclic di-GMP-dependent system regulating biosynthesis of an antifungal antibiotic in a crop-protecting bacterium, Lysobacter enzymogenes. Mol Plant Pathol 2020; 21:218-229. [PMID: 31747123 PMCID: PMC6988422 DOI: 10.1111/mpp.12890] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
YajQ, a binding protein of the universal bacterial second messenger cyclic di-GMP (c-di-GMP), affects virulence in several bacterial pathogens, including Xanthomonas campestris. In this bacterium, YajQ interacts with the transcription factor LysR. Upon c-di-GMP binding, the whole c-di-GMP-YajQ-LysR complex is found to dissociate from DNA, resulting in virulence gene regulation. Here, we identify a YajQ-LysR-like system in the bacterial biocontrol agent Lysobacter enzymogenes OH11 that secretes an antifungal antibiotic, heat-stable antifungal factor (HSAF) against crop fungal pathogens. We show that the YajQ homologue, CdgL (c-di-GMP receptor interacting with LysR) affects expression of the HSAF biosynthesis operon by interacting with the transcription activator LysR. The CdgL-LysR interaction enhances the apparent affinity of LysR to the promoter region upstream of the HSAF biosynthesis operon, which increases operon expression. Unlike the homologues CdgL (YajQ)-LysR system in X. campestris, we show that c-di-GMP binding to CdgL seems to weaken CdgL-LysR interactions and promote the release of CdgL from the LysR-DNA complex, which leads to decreased expression. Together, this study takes the YajQ-LysR-like system from bacterial pathogens to a crop-protecting bacterium that is able to regulate antifungal HSAF biosynthesis via disassembly of the c-di-GMP receptor-transcription activator complex.
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Affiliation(s)
- Sen Han
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjing210095P.R. China
| | - Danyu Shen
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjing210095P.R. China
| | - Yu‐Chuan Wang
- Institute of Biochemistry, and NCHU Agricultural Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
| | - Shan‐Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
| | - Mark Gomelsky
- Department of Molecular BiologyUniversity of WyomingLaramieWyoming82071USA
| | - Yong‐Gui Gao
- School of Biological SciencesNanyang Technological University60 Nanyang DriveSingapore637551Singapore
| | - Guoliang Qian
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjing210095P.R. China
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25
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Cao XQ, Ouyang XY, Chen B, Song K, Zhou L, Jiang BL, Tang JL, Ji G, Poplawsky AR, He YW. Genetic Interference Analysis Reveals that Both 3-Hydroxybenzoic Acid and 4-Hydroxybenzoic Acid Are Involved in Xanthomonadin Biosynthesis in the Phytopathogen Xanthomonas campestris pv. campestris. Phytopathology 2020; 110:278-286. [PMID: 31613175 DOI: 10.1094/phyto-08-19-0299-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A characteristic feature of phytopathogenic Xanthomonas bacteria is the production of yellow membrane-bound pigments called xanthomonadins. Previous studies showed that 3-hydroxybenzoic acid (3-HBA) was a xanthomonadin biosynthetic intermediate and also, that it had a signaling role. The question of whether the structural isomers 4-HBA and 2-HBA (salicylic acid) have any role in xanthomonadin biosynthesis remained unclear. In this study, we have selectively eliminated 3-HBA, 4-HBA, or the production of both by expression of the mhb, pobA, and pchAB gene clusters in the Xanthomonas campestris pv. campestris strain XC1. The resulting strains were different in pigmentation, virulence factor production, and virulence. These results suggest that both 3-HBA and 4-HBA are involved in xanthomonadin biosynthesis. When both 3-HBA and 4-HBA are present, X. campestris pv. campestris prefers 3-HBA for Xanthomonadin-A biosynthesis; the 3-HBA-derived Xanthomonadin-A was predominant over the 4-HBA-derived xanthomonadin in the wild-type strain XC1. If 3-HBA is not present, then 4-HBA is used for biosynthesis of a structurally uncharacterized Xanthomonadin-B. Salicylic acid had no effect on xanthomonadin biosynthesis. Interference with 3-HBA and 4-HBA biosynthesis also affected X. campestris pv. campestris virulence factor production and reduced virulence in cabbage and Chinese radish. These findings add to our understanding of xanthomonadin biosynthetic mechanisms and further help to elucidate the biological roles of xanthomonadins in X. campestris pv. campestris adaptation and virulence in host plants.
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Affiliation(s)
- Xue-Qiang Cao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xing-Yu Ouyang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bo Chen
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Kai Song
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lian Zhou
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bo-Le Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Guanghai Ji
- Key Laboratory of Agriculture Biodiversity for Plant Disease Management, Ministry of Education, College of Plant Protection, Yunnan Agricultural University, Kunming 650201, China
| | - Alan R Poplawsky
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, U.S.A
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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26
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Yu Y, Ma J, Guo Q, Ma J, Wang H. A novel 3-oxoacyl-ACP reductase (FabG3) is involved in the xanthomonadin biosynthesis of Xanthomonas campestris pv. campestris. Mol Plant Pathol 2019; 20:1696-1709. [PMID: 31560825 PMCID: PMC6859482 DOI: 10.1111/mpp.12871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot in crucifers, produces a membrane-bound yellow pigment called xanthomonadin to protect against photobiological and peroxidative damage, and uses a quorum-sensing mechanism mediated by the diffusible signal factor (DSF) family signals to regulate virulence factors production. The Xcc gene XCC4003, annotated as Xcc fabG3, is located in the pig cluster, which may be responsible for xanthomonadin synthesis. We report that fabG3 expression restored the growth of the Escherichia coli fabG temperature-sensitive mutant CL104 under non-permissive conditions. In vitro assays demonstrated that FabG3 catalyses the reduction of 3-oxoacyl-acyl carrier protein (ACP) intermediates in fatty acid synthetic reactions, although FabG3 had a lower activity than FabG1. Moreover, the fabG3 deletion did not affect growth or fatty acid composition. These results indicate that Xcc fabG3 encodes a 3-oxoacyl-ACP reductase, but is not essential for growth or fatty acid synthesis. However, the Xcc fabG3 knock-out mutant abolished xanthomonadin production, which could be only restored by wild-type fabG3, but not by other 3-oxoacyl-ACP reductase-encoding genes, indicating that Xcc FabG3 is specifically involved in xanthomonadin biosynthesis. Additionally, our study also shows that the Xcc fabG3-disrupted mutant affects Xcc virulence in host plants.
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Affiliation(s)
- Yonghong Yu
- Guangdong Food and Drug Vocational CollegeGuangzhouGuangdong510520China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Jianrong Ma
- Guangdong Food and Drug Vocational CollegeGuangzhouGuangdong510520China
| | - Qiaoqiao Guo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Jincheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
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Cheng ST, Wang FF, Qian W. Cyclic-di-GMP binds to histidine kinase RavS to control RavS-RavR phosphotransfer and regulates the bacterial lifestyle transition between virulence and swimming. PLoS Pathog 2019; 15:e1007952. [PMID: 31408509 PMCID: PMC6707612 DOI: 10.1371/journal.ppat.1007952] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 08/23/2019] [Accepted: 06/30/2019] [Indexed: 12/28/2022] Open
Abstract
The two-component signalling system (TCS) comprising a histidine kinase (HK) and a response regulator (RR) is the predominant bacterial sense-and-response machinery. Because bacterial cells usually encode a number of TCSs to adapt to various ecological niches, the specificity of a TCS is in the centre of regulation. Specificity of TCS is defined by the capability and velocity of phosphoryl transfer between a cognate HK and a RR. Here, we provide genetic, enzymology and structural data demonstrating that the second messenger cyclic-di-GMP physically and specifically binds to RavS, a HK of the phytopathogenic, gram-negative bacterium Xanthomonas campestris pv. campestris. The [c-di-GMP]-RavS interaction substantially promotes specificity between RavS and RavR, a GGDEF–EAL domain-containing RR, by reinforcing the kinetic preference of RavS to phosphorylate RavR. [c-di-GMP]-RavS binding effectively decreases the phosphorylation level of RavS and negatively regulates bacterial swimming. Intriguingly, the EAL domain of RavR counteracts the above regulation by degrading c-di-GMP and then increasing the level of phosphorylated RavS. Therefore, RavR acts as a bifunctional phosphate sink that finely controls the level of phosphorylated RavS. These biochemical processes interactively modulate the phosphoryl flux between RavS-RavR and bacterial lifestyle transition. Our results revealed that c-di-GMP acts as an allosteric effector to dynamically modulate specificity between HK and RR. c-di-GMP is a multifunctional bacterial second messenger that controls various physiological processes. The nucleotide derivative binds to riboswitches or proteins as effectors during regulation. Here, we found that c-di-GMP physically binds to a histidine kinase, RavS, of a plant pathogenic bacterium. The binding event significantly enhanced the phosphotransferase activity of RavS to phosphorylate a response regulator, RavR. This process tightly modulates the phosphorylation level of RavS, which is important to the lifestyle transition of the bacterium between virulence and swimming motility. Therefore, our results reveal that c-di-GMP controls the bacterial two-component signalling, one of the dominant mechanisms of bacterial cells in adaptation to various environmental stimuli.
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Affiliation(s)
- Shou-Ting Cheng
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Plant Genomics, Institution of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Wang
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Biotic Interactions, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Leng M, Lu Z, Qin Z, Qi Y, Lu G, Tang J. Flp, a Fis-like protein, contributes to the regulation of type III secretion and virulence processes in the phytopathogen Xanthomonas campestris pv. campestris. Mol Plant Pathol 2019; 20:1119-1133. [PMID: 31090173 PMCID: PMC6640185 DOI: 10.1111/mpp.12818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The ability of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) to cause disease is dependent on its ability to adapt quickly to the host environment during infection. Like most bacterial pathogens, Xcc has evolved complex regulatory networks that ensure expression and regulation of their virulence genes. Here, we describe the identification and characterization of a Fis-like protein (named Flp), which plays an important role in virulence and type III secretion system (T3SS) gene expression in Xcc. Deletion of flp caused reduced virulence and hypersensitive response (HR) induction of Xcc and alterations in stress tolerance. Global transcriptome analyses revealed the Flp had a broad regulatory role and that most T3SS HR and pathogenicity (hrp) genes were down-regulated in the flp mutant. β-glucuronidase activity assays implied that Flp regulates the expression of hrp genes via controlling the expression of hrpX. More assays confirmed that Flp binds to the promoter of hrpX and affected the transcription of hrpX directly. Interestingly, the constitutive expression of hrpX in the flp mutant restored the HR phenotype but not full virulence. Taken together, the findings describe the unrecognized regulatory role of Flp protein that controls hrp gene expression and pathogenesis in Xcc.
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Affiliation(s)
- Ming Leng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources, College of Life Science and TechnologyGuangxi University100 Daxue RoadNanningGuangxi530004China
| | - Zhuo‐Jian Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources, College of Life Science and TechnologyGuangxi University100 Daxue RoadNanningGuangxi530004China
| | - Zuo‐Shu Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources, College of Life Science and TechnologyGuangxi University100 Daxue RoadNanningGuangxi530004China
| | - Yan‐Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources, College of Life Science and TechnologyGuangxi University100 Daxue RoadNanningGuangxi530004China
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources, College of Life Science and TechnologyGuangxi University100 Daxue RoadNanningGuangxi530004China
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources, College of Life Science and TechnologyGuangxi University100 Daxue RoadNanningGuangxi530004China
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Rodrigues PR, Assis DJ, Druzian JI. Simultaneous production of polyhydroxyalkanoate and xanthan gum: From axenic to mixed cultivation. Bioresour Technol 2019; 283:332-339. [PMID: 30925313 DOI: 10.1016/j.biortech.2019.03.095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
In the present study, mixed and axenic submerged cultures of Cupriavidus necator and Xanthomonas campestris were performed for simultaneous and individual PHA and XG productions using palm oil (Elaeis guineensis) as substrate. Rotational Central Compound Design (RCCD) was successfully used in the optimization of individual productions of PHA (3.39 g L-1, Mw = 692.6 kDa) and XG (1.77 g L-1, Mw = 36.6 × 105 kDa). Novel simultaneous production of PHA (6.43 g L-1, Mw = 629.2 kDa) and XG (1.98 g L-1, Mw = 25.0 × 105 kDa), executed in bacterial co-cultivation, revealed to be a successful strategy to increment polymer synthesis, especially PHA. XG bioconversions followed a general trend of lower production in co-culture. Culture configurations also altered polymers properties and characteristics.
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Affiliation(s)
- Plínio R Rodrigues
- University of Campinas - UNICAMP, Graduate Program in Chemical Engineering, Av. Albert Einstein, n 500, Cidade Universitária, 13083-852 Campinas, SP, Brazil.
| | - Denilson J Assis
- Federal University of Bahia - UFBA, Graduate Program in Chemical Engineering, Rua Aristides Novis, n 2, Federação, 40210-630 Salvador, BA, Brazil
| | - Janice I Druzian
- Federal University of Bahia - UFBA, Graduate Program in Chemical Engineering, Rua Aristides Novis, n 2, Federação, 40210-630 Salvador, BA, Brazil
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Wu J, Pan X, Xu S, Duan Y, Luo J, Zhou Z, Wang J, Zhou M. The critical role of cytochrome c maturation (CCM) system in the tolerance of Xanthomonas campestris pv. campestris to phenazines. Pestic Biochem Physiol 2019; 156:63-71. [PMID: 31027582 DOI: 10.1016/j.pestbp.2019.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/29/2019] [Accepted: 02/05/2019] [Indexed: 06/09/2023]
Abstract
Phenazine-1-carboxylic acid (PCA), a secondary metabolite produced by Pseudomonas spp., exhibits a high inhibitory effect in Xanthomonas oryzae pv. oryzae (Xoo), but less inhibitory effect in Xanthomonas oryzae pv. oryzicola (Xoc), and almost no inhibitory effect in Xanthomonas campestris pv. campestris (Xcc). In our previous study, reactive oxygen species (ROS) scavenging system was reported to be involved in PCA tolerance in Xanthomonas spp. However, the PCA tolerance mechanism of Xanthomonas spp. is unclear. In the current study, we constructed a Tn5-based transposon mutant library in Xcc and four highly PCA-sensitive insertion mutants were obtained. TAIL-PCR further confirmed that the Tn5 transposon was inserted in the cytochrome c maturation (CCM) system (XC_1893, XC_1897) of these mutants. Disruption of the CCM system significantly decreased the growth, motility and tolerance of Xcc to PCA and other phenazines, such as phenazine and 1-OH-phenazine. The CCM system is responsible for the covalent attachment of the apocytochrome and heme. Disruption of the transmembrane thioredox protein (Dsb) pathway (XC_0531), an essential process for the formation of mature apocytochrome, also exhibited a decreased tolerance to PCA, suggesting that the defect of cytochrome c caused decreased tolerance of Xcc to PCA. Meanwhile, disruption of the CCM system or Dsb pathway interfered with the functions of cytochrome c proteins, causing an increased sensitivity to H2O2. Collectively, we concluded that the CCM system and Dsb pathway, regulate the tolerance of Xcc to phenazines by influencing the functions of cytochrome c. Therefore, these results provide important references for revealing the action mechanism of PCA in Xanthomonas spp.
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Affiliation(s)
- Jian Wu
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiayan Pan
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Shu Xu
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Yabing Duan
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianying Luo
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Zehua Zhou
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianxin Wang
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China
| | - Mingguo Zhou
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China.
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Zhang C, Lv M, Yin W, Dong T, Chang C, Miao Y, Jia Y, Deng Y. Xanthomonas campestris Promotes Diffusible Signal Factor Biosynthesis and Pathogenicity by Utilizing Glucose and Sucrose from Host Plants. Mol Plant Microbe Interact 2019; 32:157-166. [PMID: 30156480 DOI: 10.1094/mpmi-07-18-0187-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The plant pathogen Xanthomonas campestris pv. campestris produces diffusible signal factor (DSF) quorum sensing (QS) signals to regulate its biological functions and virulence. Our previous study showed that X. campestris pv. campestris utilizes host plant metabolites to enhance the biosynthesis of DSF family signals. However, it is unclear how X. campestris pv. campestris benefits from the metabolic products of the host plant. In this study, we observed that the host plant metabolites not only boosted the production of the DSF family signals but also modulated the expression levels of DSF-regulated genes in X. campestris pv. campestris. Infection with X. campestris pv. campestris induced changes in the expression of many sugar transporter genes in Arabidopsis thaliana. Exogenous addition of sucrose or glucose, which are the major products of photosynthesis in plants, enhanced DSF signal production and X. campestris pv. campestris pathogenicity in the Arabidopsis model. In addition, several sucrose hydrolase-encoding genes in X. campestris pv. campestris and sucrose invertase-encoding genes in the host plant were notably upregulated during the infection process. These enzymes hydrolyzed sucrose to glucose and fructose, and in trans expression of one of these enzymes, CINV1 of A. thaliana or XC_0805 of X. campestris pv. campestris, enhanced DSF signal biosynthesis in X. campestris pv. campestris in the presence of sucrose. Taken together, our findings demonstrate that X. campestris pv. campestris applies multiple strategies to utilize host plant sugars to enhance QS and pathogenicity.
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Affiliation(s)
- Chunyan Zhang
- 1 State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- 2 Guangdong Innovative Research Team of Sociomicrobiology, College of Agriculture, South China Agricultural University
| | - Mingfa Lv
- 3 Integrative Microbiology Research Centre, South China Agricultural University
| | - Wenfang Yin
- 1 State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- 2 Guangdong Innovative Research Team of Sociomicrobiology, College of Agriculture, South China Agricultural University
| | - Tingyan Dong
- 1 State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- 2 Guangdong Innovative Research Team of Sociomicrobiology, College of Agriculture, South China Agricultural University
| | - Changqing Chang
- 2 Guangdong Innovative Research Team of Sociomicrobiology, College of Agriculture, South China Agricultural University
- 3 Integrative Microbiology Research Centre, South China Agricultural University
| | - Yansong Miao
- 4 School of Biological Sciences, Nanyang Technological University, Singapore 637551; and
| | - Yantao Jia
- 5 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yinyue Deng
- 1 State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- 2 Guangdong Innovative Research Team of Sociomicrobiology, College of Agriculture, South China Agricultural University
- 3 Integrative Microbiology Research Centre, South China Agricultural University
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Zhang JL, Wang D, Liang YW, Zhong WY, Ming ZH, Tang DJ, Tang JL. The Gram-negative phytopathogen Xanthomonas campestris pv. campestris employs a 5'UTR as a feedback controller to regulate methionine biosynthesis. Microbiology (Reading) 2018; 164:1146-1155. [PMID: 30024369 PMCID: PMC6230763 DOI: 10.1099/mic.0.000690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis of methionine is critical for most bacteria. It is known that cellular methionine has a feedback effect on the expression of met genes involved in de novo methionine biosynthesis. Previous studies revealed that Gram-negative bacteria control met gene expression at the transcriptional level by regulator proteins, while most Gram-positive bacteria regulate met genes at post-transcriptional level by RNA regulators (riboregulators) located in the 5′UTR of met genes. However, despite its importance, the methionine biosynthesis pathway in the Gram-negative Xanthomonas genus that includes many important plant pathogens is completely uncharacterized. Here, we address this issue using the crucifer black rot pathogen Xanthomonas campestris pv. campestris (Xcc), a model bacterium in microbe–plant interaction studies. The work identified an operon (met) involved in de novo methionine biosynthesis in Xcc. Disruption of the operon resulted in defective growth in methionine-limited media and in planta. Western blot analysis revealed that the expression of the operon is dependent on methionine levels. Further molecular analyses demonstrated that the 5′UTR, but not the promoter of the operon, is involved in feedback regulation on operon expression in response to methionine availability, providing an example of a Gram-negative bacterium utilizing a 5′UTR region to control the expression of the genes involved in methionine biosynthesis.
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Affiliation(s)
- Jian-Ling Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
| | - Dan Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
| | - Yu-Wei Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
| | - Wan-Ying Zhong
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
| | - Zhen-Hua Ming
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
| | - Dong-Jie Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
- *Correspondence: Dong-Jie Tang,
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, PR China
- Ji-Liang Tang,
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Choi S, Jayaraman J, Sohn KH. Arabidopsis thaliana SOBER1 (SUPPRESSOR OF AVRBST-ELICITED RESISTANCE 1) suppresses plant immunity triggered by multiple bacterial acetyltransferase effectors. New Phytol 2018; 219:324-335. [PMID: 29577317 DOI: 10.1111/nph.15125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/19/2018] [Indexed: 05/21/2023]
Abstract
Plants evolved disease resistance (R) proteins that recognize corresponding pathogen effectors and activate effector-triggered immunity (ETI). However, it is largely unknown why, in some cases, a suppressor of ETI exists in plants. Arabidopsis SOBER1 (Suppressor of AvrBsT-elicited Resistance 1) was identified previously as a suppressor of Xanthomonas acetyltransferase effector AvrBsT-triggered immunity. Nevertheless, the extent to which SOBER1 suppresses ETI is unclear. Here, we identified SOBER1 as a suppressor of Pseudomonas acetyltransferase effector HopZ5-triggered immunity in Arabidopsis using recombinant inbred lines. Further analysis showed that SOBER1 suppresses immunity triggered by multiple bacterial acetyltransferases. Interestingly, SOBER1 interferes with the immunity signalling activated by some but not all tested acetyltransferase effectors, indicating that SOBER1 might target components that are shared between several ETI pathways.
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Affiliation(s)
- Sera Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Korea
- Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Palmerston North, 4474, New Zealand
| | - Jay Jayaraman
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Korea
- Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Palmerston North, 4474, New Zealand
- New Zealand Institute for Plant & Food Research Limited (PFR), Mt Albert, Auckland, 1025, New Zealand
| | - Kee Hoon Sohn
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Korea
- Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Palmerston North, 4474, New Zealand
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Korea
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Erickson JL, Adlung N, Lampe C, Bonas U, Schattat MH. The Xanthomonas effector XopL uncovers the role of microtubules in stromule extension and dynamics in Nicotiana benthamiana. Plant J 2018; 93:856-870. [PMID: 29285819 DOI: 10.1111/tpj.13813] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/04/2017] [Accepted: 12/08/2017] [Indexed: 05/26/2023]
Abstract
Xanthomonas campestris pv. vesicatoria type III-secreted effectors were screened for candidates influencing plant cell processes relevant to the formation and maintenance of stromules in Nicotiana benthamiana lower leaf epidermis. Transient expression of XopL, a unique type of E3 ubiquitin ligase, led to a nearly complete elimination of stromules and the relocation of plastids to the nucleus. Further characterization of XopL revealed that the E3 ligase activity is essential for the two plastid phenotypes. In contrast to the XopL wild type, a mutant XopL lacking E3 ligase activity specifically localized to microtubules. Interestingly, mutant XopL-labeled filaments frequently aligned with stromules, suggesting an important, yet unexplored, microtubule-stromule relationship. High time-resolution movies confirmed that microtubules provide a scaffold for stromule movement and contribute to stromule shape. Taken together, this study has defined two populations of stromules: microtubule-dependent stromules, which were found to move slower and persist longer, and microtubule-independent stromules, which move faster and are transient. Our results provide the basis for a new model of stromule dynamics including interactions with both actin and microtubules.
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Affiliation(s)
- Jessica L Erickson
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
| | - Norman Adlung
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
| | - Christina Lampe
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
| | - Ulla Bonas
- Department of Genetics, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
| | - Martin H Schattat
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099, Halle, Germany
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Pan Y, Liang F, Li RJ, Qian W. MarR-Family Transcription Factor HpaR Controls Expression of the vgrR-vgrS Operon of Xanthomonas campestris pv. campestris. Mol Plant Microbe Interact 2018; 31:299-310. [PMID: 29077520 DOI: 10.1094/mpmi-07-17-0187-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
MarR (multiple antibiotic resistance regulator)-family transcription factors (TFs), which regulate the expression of virulence factors and other physiological pathways in pathogenic bacteria, are regarded as ideal molecular targets for the development of novel antimicrobial strategies. In the plant bacterial pathogen Xanthomonas campestris pv. campestris, HpaR, a typical MarR-family TF, is associated with bacterial virulence, but its mechanism of virulence regulation remains unclear. Here, we dissected the HpaR regulon using high-throughput RNA sequencing and chromatin immunoprecipitation sequencing. HpaR directly or indirectly controls the expression of approximately 448 genes; it acts both as a transcriptional activator and a repressor to control the expression of downstream genes by directly binding to their promoter regions. The consensus HpaR-binding DNA motifs contain imperfect palindromic sequences similar to [G/T]CAACAATT[C/T]TTG. In-depth analysis revealed that HpaR positively modulates transcription level of the vgrR-vgrS operon that encodes an important two-component signal transduction system to sense iron depletion and regulate bacterial virulence. Epistasis analysis demonstrated that vgrR-vgrS is a core downstream component of HpaR regulation, as overexpression of vgrR restored the phenotypic deficiencies caused by a hpaR mutation. This dissection of the HpaR regulon should facilitate future studies focused on the activating mechanism of HpaR during bacterial infection.
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Affiliation(s)
- Yue Pan
- 1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- 2 School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; and
| | - Fang Liang
- 3 Beijing Institute of Genomics, Chinese Academy of Sciences
| | - Ru-Jiao Li
- 3 Beijing Institute of Genomics, Chinese Academy of Sciences
| | - Wei Qian
- 1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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Scheibner F, Hartmann N, Hausner J, Lorenz C, Hoffmeister AK, Büttner D. The Type III Secretion Chaperone HpaB Controls the Translocation of Effector and Noneffector Proteins From Xanthomonas campestris pv. vesicatoria. Mol Plant Microbe Interact 2018; 31:61-74. [PMID: 28771395 DOI: 10.1094/mpmi-06-17-0138-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pathogenicity of the gram-negative bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion (T3S) system, which translocates effector proteins into plant cells. Effector proteins contain N-terminal T3S and translocation signals and interact with the T3S chaperone HpaB, which presumably escorts effectors to the secretion apparatus. The molecular mechanisms underlying the recognition of effectors by the T3S system are not yet understood. In the present study, we analyzed T3S and translocation signals in the type III effectors XopE2 and XopJ from X. campestris pv. vesicatoria. Both effectors contain minimal translocation signals, which are only recognized in the absence of HpaB. Additional N-terminal signals promote translocation of XopE2 and XopJ in the wild-type strain. The results of translocation and interaction studies revealed that the interaction of XopE2 and XopJ with HpaB and a predicted cytoplasmic substrate docking site of the T3S system is not sufficient for translocation. In agreement with this finding, we show that the presence of an artificial HpaB-binding site does not promote translocation of the noneffector XopA in the wild-type strain. Our data, therefore, suggest that the T3S chaperone HpaB not only acts as an escort protein but also controls the recognition of translocation signals.
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Affiliation(s)
- Felix Scheibner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Nadine Hartmann
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Jens Hausner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Christian Lorenz
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Anne-Katrin Hoffmeister
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Daniela Büttner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
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Blüher D, Laha D, Thieme S, Hofer A, Eschen-Lippold L, Masch A, Balcke G, Pavlovic I, Nagel O, Schonsky A, Hinkelmann R, Wörner J, Parvin N, Greiner R, Weber S, Tissier A, Schutkowski M, Lee J, Jessen H, Schaaf G, Bonas U. A 1-phytase type III effector interferes with plant hormone signaling. Nat Commun 2017; 8:2159. [PMID: 29255246 PMCID: PMC5735085 DOI: 10.1038/s41467-017-02195-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022] Open
Abstract
Most Gram-negative phytopathogenic bacteria inject type III effector (T3E) proteins into plant cells to manipulate signaling pathways to the pathogen's benefit. In resistant plants, specialized immune receptors recognize single T3Es or their biochemical activities, thus halting pathogen ingress. However, molecular function and mode of recognition for most T3Es remains elusive. Here, we show that the Xanthomonas T3E XopH possesses phytase activity, i.e., dephosphorylates phytate (myo-inositol-hexakisphosphate, InsP6), the major phosphate storage compound in plants, which is also involved in pathogen defense. A combination of biochemical approaches, including a new NMR-based method to discriminate inositol polyphosphate enantiomers, identifies XopH as a naturally occurring 1-phytase that dephosphorylates InsP6 at C1. Infection of Nicotiana benthamiana and pepper by Xanthomonas results in a XopH-dependent conversion of InsP6 to InsP5. 1-phytase activity is required for XopH-mediated immunity of plants carrying the Bs7 resistance gene, and for induction of jasmonate- and ethylene-responsive genes in N. benthamiana.
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Affiliation(s)
- Doreen Blüher
- Institute for Biology, Department of Genetics, Martin-Luther University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany
| | - Debabrata Laha
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, Karlrobert-Kreiten-Strasse 13, 53115, Bonn, Germany
- Center for Plant Molecular Biology, Department of Plant Physiology, Eberhard Karls University Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Sabine Thieme
- Institute for Biology, Department of Genetics, Martin-Luther University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany
| | - Alexandre Hofer
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Lennart Eschen-Lippold
- Department of Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
| | - Antonia Masch
- Institute for Biochemistry and Biotechnology, Department of Enzymology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06120, Halle (Saale), Germany
| | - Gerd Balcke
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
| | - Igor Pavlovic
- Institute of Organic Chemistry, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Oliver Nagel
- Institute for Biology, Department of Genetics, Martin-Luther University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany
| | - Antje Schonsky
- Institute for Biology, Department of Genetics, Martin-Luther University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany
| | - Rahel Hinkelmann
- Institute of Organic Chemistry, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Jakob Wörner
- Institute of Physical Chemistry, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Nargis Parvin
- Center for Plant Molecular Biology, Department of Plant Physiology, Eberhard Karls University Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Ralf Greiner
- Department of Food Technology and Bioprocess Engineering, Max-Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Straße 9, 76131, Karlsruhe, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Alain Tissier
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
| | - Mike Schutkowski
- Institute for Biochemistry and Biotechnology, Department of Enzymology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06120, Halle (Saale), Germany
| | - Justin Lee
- Department of Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
| | - Henning Jessen
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- Institute of Organic Chemistry, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany.
| | - Gabriel Schaaf
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, Karlrobert-Kreiten-Strasse 13, 53115, Bonn, Germany.
- Center for Plant Molecular Biology, Department of Plant Physiology, Eberhard Karls University Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany.
| | - Ulla Bonas
- Institute for Biology, Department of Genetics, Martin-Luther University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany.
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Liu L, Wang Y, Cui F, Fang A, Wang S, Wang J, Wei C, Li S, Sun W. The type III effector AvrXccB in Xanthomonas campestris pv. campestris targets putative methyltransferases and suppresses innate immunity in Arabidopsis. Mol Plant Pathol 2017; 18:768-782. [PMID: 27241588 PMCID: PMC6638230 DOI: 10.1111/mpp.12435] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/17/2016] [Accepted: 05/23/2016] [Indexed: 05/04/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc) causes black rot, one of the most important diseases of brassica crops worldwide. The type III effector inventory plays important roles in the virulence and pathogenicity of the pathogen. However, little is known about the virulence function(s) of the putative type III effector AvrXccB in Xcc. Here, we investigated the immune suppression ability of AvrXccB and the possible underlying mechanisms. AvrXccB was demonstrated to be secreted in a type III secretion system-dependent manner. AvrXccB tagged with green fluorescent protein is localized to the plasma membrane in Arabidopsis, and the putative N-myristoylation motif is essential for its localization. Chemical-induced expression of AvrXccB suppresses flg22-triggered callose deposition and the oxidative burst, and promotes the in planta growth of Xcc and Pseudomonas syringae pv. tomato in transgenic Arabidopsis plants. The putative catalytic triad and plasma membrane localization of AvrXccB are required for its immunosuppressive activity. Furthermore, it was demonstrated that AvrXccB interacts with the Arabidopsis S-adenosyl-l-methionine-dependent methyltransferases SAM-MT1 and SAM-MT2. Interestingly, SAM-MT1 is not only self-associated, but also associated with SAM-MT2 in vivo. SAM-MT1 and SAM-MT2 expression is significantly induced upon stimulation of microbe-associated molecular patterns and bacterial infection. Collectively, these findings indicate that AvrXccB targets a putative methyltransferase complex and suppresses plant immunity.
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Affiliation(s)
- Lijuan Liu
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Yanping Wang
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Fuhao Cui
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Anfei Fang
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Shanzhi Wang
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Jiyang Wang
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Chao Wei
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Shuai Li
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
| | - Wenxian Sun
- Department of Plant Pathology, Key Laboratory of Plant Pathology, Ministry of AgricultureChina Agricultural UniversityBeijing100193China
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Han SW, Hwang BK. Molecular functions of Xanthomonas type III effector AvrBsT and its plant interactors in cell death and defense signaling. Planta 2017; 245:237-253. [PMID: 27928637 DOI: 10.1007/s00425-016-2628-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 11/30/2016] [Indexed: 05/20/2023]
Abstract
Xanthomonas effector AvrBsT interacts with plant defense proteins and triggers cell death and defense response. This review highlights our current understanding of the molecular functions of AvrBsT and its host interactor proteins. The AvrBsT protein is a member of a growing family of effector proteins in both plant and animal pathogens. Xanthomonas type III effector AvrBsT, a member of the YopJ/AvrRxv family, suppresses plant defense responses in susceptible hosts, but triggers cell death signaling leading to hypersensitive response (HR) and defense responses in resistant plants. AvrBsT interacts with host defense-related proteins to trigger the HR cell death and defense responses in plants. Here, we review and discuss recent progress in understanding the molecular functions of AvrBsT and its host interactor proteins in pepper (Capsicum annuum). Pepper arginine decarboxylase1 (CaADC1), pepper aldehyde dehydrogenase1 (CaALDH1), pepper heat shock protein 70a (CaHSP70a), pepper suppressor of the G2 allele of skp1 (CaSGT1), pepper SNF1-related kinase1 (SnRK1), and Arabidopsis acetylated interacting protein1 (ACIP1) have been identified as AvrBsT interactors in pepper and Arabidopsis. Gene expression profiling, virus-induced gene silencing, and transient transgenic overexpression approaches have advanced the functional characterization of AvrBsT-interacting proteins in plants. AvrBsT is localized in the cytoplasm and forms protein-protein complexes with host interactors. All identified AvrBsT interactors regulate HR cell death and defense responses in plants. Notably, CaSGT1 physically binds to both AvrBsT and pepper receptor-like cytoplasmic kinase1 (CaPIK1) in the cytoplasm. During infection with Xanthomonas campestris pv. vesicatoria strain Ds1 (avrBsT), AvrBsT is phosphorylated by CaPIK1 and forms the active AvrBsT-CaSGT1-CaPIK1 complex, which ultimately triggers HR cell death and defense responses. Collectively, the AvrBsT interactor proteins are involved in plant cell death and immunity signaling.
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Affiliation(s)
- Sang Wook Han
- Department of Integrative Plant Science, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Byung Kook Hwang
- Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul, 02841, Republic of Korea.
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Wang L, Pan Y, Yuan ZH, Zhang H, Peng BY, Wang FF, Qian W. Two-Component Signaling System VgrRS Directly Senses Extracytoplasmic and Intracellular Iron to Control Bacterial Adaptation under Iron Depleted Stress. PLoS Pathog 2016; 12:e1006133. [PMID: 28036380 PMCID: PMC5231390 DOI: 10.1371/journal.ppat.1006133] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/12/2017] [Accepted: 12/16/2016] [Indexed: 12/02/2022] Open
Abstract
Both iron starvation and excess are detrimental to cellular life, especially for animal and plant pathogens since they always live in iron-limited environments produced by host immune responses. However, how organisms sense and respond to iron is incompletely understood. Herein, we reveal that in the phytopathogenic bacterium Xanthomonas campestris pv. campestris, VgrS (also named ColS) is a membrane-bound receptor histidine kinase that senses extracytoplasmic iron limitation in the periplasm, while its cognate response regulator, VgrR (ColR), detects intracellular iron excess. Under iron-depleted conditions, dissociation of Fe3+ from the periplasmic sensor region of VgrS activates the VgrS autophosphorylation and subsequent phosphotransfer to VgrR, an OmpR-family transcription factor that regulates bacterial responses to take up iron. VgrR-VgrS regulon and the consensus DNA binding motif of the transcription factor VgrR were dissected by comparative proteomic and ChIP-seq analyses, which revealed that in reacting to iron-depleted environments, VgrR directly or indirectly controls the expressions of hundreds of genes that are involved in various physiological cascades, especially those associated with iron-uptake. Among them, we demonstrated that the phosphorylated VgrR tightly represses the transcription of a special TonB-dependent receptor gene, tdvA. This regulation is a critical prerequisite for efficient iron uptake and bacterial virulence since activation of tdvA transcription is detrimental to these processes. When the intracellular iron accumulates, the VgrR-Fe2+ interaction dissociates not only the binding between VgrR and the tdvA promoter, but also the interaction between VgrR and VgrS. This relieves the repression in tdvA transcription to impede continuous iron uptake and avoids possible toxic effects of excessive iron accumulation. Our results revealed a signaling system that directly senses both extracytoplasmic and intracellular iron to modulate bacterial iron homeostasis. The biological function of iron is like a “double-edge sword” to all cellular life since iron starvation or iron excess leads to cell death. For animal and plant pathogens, they have to compete for iron with their hosts since iron-limitation generally is an immune response against microbial infection. However, how pathogens detect extracellular and intracellular iron concentrations remains unclear. Here we show that a plant bacterial pathogen employs a membrane-bound sensor histidine kinase, VgrS, to directly detect extracytoplasmic iron starvation and activate iron uptake accordingly. As a prerequisite, VgrS phosphorylates cognate VgrR to shut down the transcription of a downstream gene, tdvA, whose expression is harmful to absorb iron and bacterial virulence. However, as intracellular iron concentration increases, the ferrous iron binds to VgrR to release its repression on the tdvA transcription, which results in the block of continuous iron uptake to avoid toxic effect of the metal. Therefore, VgrS and VgrR detect extracytoplasmic and intracellular iron, respectively, and systematically modulate cellular homeostasis to promote bacterial survival in iron-depleted environments, such as in host plant.
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Affiliation(s)
- Li Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yue Pan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Hui Yuan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Huan Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Bao-Yu Peng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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41
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Teckentrup J, Al-Hammood O, Steffens T, Bednarz H, Walhorn V, Niehaus K, Anselmetti D. Comparative analysis of different xanthan samples by atomic force microscopy. J Biotechnol 2016; 257:2-8. [PMID: 27919690 DOI: 10.1016/j.jbiotec.2016.11.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/30/2016] [Accepted: 11/30/2016] [Indexed: 02/04/2023]
Abstract
The polysaccharide xanthan which is produced by the γ-proteobacterium Xanthomonas campestris is used as a food thickening agent and rheologic modifier in numerous food, cosmetics and technical applications. Its great commercial importance stimulated biotechnological approaches to optimize the xanthan production. By targeted genetic modification the metabolism of Xanthomonas can be modified in such a way that the xanthan production efficiency and/or the shear-thickening potency is optimized. Using atomic force microscopy (AFM) the secondary structure of single xanthan polymers produced by the wild type Xanthomonas campestris B100 and several genetically modified variations were analyzed. We found a wide variation of characteristic differences between xanthan molecules produced by different strains. The structures ranged from single-stranded coiled polymers to branched xanthan double-strands. These results can help to get a better understanding of the polymerization- and secretion-machinery that are relevant for xanthan synthesis. Furthermore, we demonstrate that the xanthan secondary structure strongly correlates with its viscosifying properties.
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Affiliation(s)
- Julia Teckentrup
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Germany.
| | - Orooba Al-Hammood
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Germany.
| | - Tim Steffens
- Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Germany.
| | - Hanna Bednarz
- Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Germany.
| | - Volker Walhorn
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Germany.
| | - Karsten Niehaus
- Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Germany.
| | - Dario Anselmetti
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Germany.
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Zhao Z, Wu Z, Zhang J. Crystal structure of the YajQ-family protein XC_3703 from Xanthomonas campestris pv. campestris. Acta Crystallogr F Struct Biol Commun 2016; 72:720-5. [PMID: 27599864 PMCID: PMC5012213 DOI: 10.1107/s2053230x16013017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/11/2016] [Indexed: 11/10/2022] Open
Abstract
As an important bacterial second messenger, bis-(3',5')-cyclic diguanylate (cyclic di-GMP or c-di-GMP) has been implicated in numerous biological activities, including biofilm formation, motility, survival and virulence. These processes are manipulated by the binding of c-di-GMP to its receptors. XC_3703 from the plant pathogen Xanthomonas campestris pv. campestris, which belongs to the YajQ family of proteins, has recently been identified as a potential c-di-GMP receptor. XC_3703, together with XC_2801, functions as a transcription factor activating virulence-related genes, which can be reversed by the binding of c-di-GMP to XC_3703. However, the structural basis of how c-di-GMP regulates XC_3703 remains elusive. In this study, the structure of XC_3703 was determined to 2.1 Å resolution using the molecular-replacement method. The structure of XC_3703 consists of two domains adopting the same topology, which is similar to that of the RNA-recognition motif (RRM). Arg65, which is conserved among the c-di-GMP-binding subfamily of the YajQ family of proteins, together with Phe80 in domain II, forms a putative c-di-GMP binding site.
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Affiliation(s)
- Zhixin Zhao
- College of Biology, Pharmacy and Food Engineering, Shangluo University, Shangluo 726000, People’s Republic of China
| | - Zhen Wu
- College of Biology, Pharmacy and Food Engineering, Shangluo University, Shangluo 726000, People’s Republic of China
| | - Jun Zhang
- College of Biology, Pharmacy and Food Engineering, Shangluo University, Shangluo 726000, People’s Republic of China
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43
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Wang Z, Wu J, Zhu L, Zhan X. Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol. Bioresour Technol 2016; 211:390-7. [PMID: 27030959 DOI: 10.1016/j.biortech.2016.03.096] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/14/2016] [Accepted: 03/17/2016] [Indexed: 05/06/2023]
Abstract
Many studies have focused on using crude glycerol from biodiesel to obtain valuable products, but few of these studies have focused on obtaining polysaccharides. A mutant strain of Xanthomonas campestris CCTCC M2015714 that could use glycerol to produce high-transparency and low-viscosity xanthan gum was obtained by adaptive evolution, and the yield of xanthan gum reached 11.0g/L. We found that transcriptional levels of genes related to glycerol metabolism (glpF, glpK, glpD, and fbp) in the mutant strain were all higher than those from the parent strain. Using 5g/L sucrose or glucose as starter substrate, cell growth time decreased from 36h to 24h and xanthan gum yield increased. Moreover, the mutant strain can tolerate high titer glycerol, and its activity was not affected by the impurities in crude glycerol. All these results proved that crude glycerol from biodiesel industries can be used for xanthan gum production.
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Affiliation(s)
- Zichao Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jianrong Wu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Li Zhu
- Wuxi Galaxy Biotech Co. Ltd., Wuxi, Jiangsu 214125, China
| | - Xiaobei Zhan
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China.
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Abstract
Intracellular nucleotide-binding leucine-rich repeat (NLR) receptors play central roles in human and plant innate immunity. In this issue of Cell Host & Microbe, Wang et al. (2015) show that a single plant NLR can detect diverse pathogen effectors by partnering with different scaffolding proteins, which can each recognize distinct effector targets.
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Affiliation(s)
- Roger W Innes
- Department of Biology, Indiana University, 915 East Third Street, Bloomington, IN 47405, USA.
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Scheibner F, Schulz S, Hausner J, Marillonnet S, Büttner D. Type III-Dependent Translocation of HrpB2 by a Nonpathogenic hpaABC Mutant of the Plant-Pathogenic Bacterium Xanthomonas campestris pv. vesicatoria. Appl Environ Microbiol 2016; 82:3331-3347. [PMID: 27016569 PMCID: PMC4959247 DOI: 10.1128/aem.00537-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 03/21/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria employs a type III secretion (T3S) system to translocate effector proteins into plant cells. The T3S apparatus spans both bacterial membranes and is associated with an extracellular pilus and a channel-like translocon in the host plasma membrane. T3S is controlled by the switch protein HpaC, which suppresses secretion and translocation of the predicted inner rod protein HrpB2 and promotes secretion of translocon and effector proteins. We previously reported that HrpB2 interacts with HpaC and the cytoplasmic domain of the inner membrane protein HrcU (C. Lorenz, S. Schulz, T. Wolsch, O. Rossier, U. Bonas, and D. Büttner, PLoS Pathog 4:e1000094, 2008, http://dx.doi.org/10.1371/journal.ppat.1000094). However, the molecular mechanisms underlying the control of HrpB2 secretion are not yet understood. Here, we located a T3S and translocation signal in the N-terminal 40 amino acids of HrpB2. The results of complementation experiments with HrpB2 deletion derivatives revealed that the T3S signal of HrpB2 is essential for protein function. Furthermore, interaction studies showed that the N-terminal region of HrpB2 interacts with the cytoplasmic domain of HrcU, suggesting that the T3S signal of HrpB2 contributes to substrate docking. Translocation of HrpB2 is suppressed not only by HpaC but also by the T3S chaperone HpaB and its secreted regulator, HpaA. Deletion of hpaA, hpaB, and hpaC leads to a loss of pathogenicity but allows the translocation of fusion proteins between the HrpB2 T3S signal and effector proteins into leaves of host and non-host plants. IMPORTANCE The T3S system of the plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria is essential for pathogenicity and delivers effector proteins into plant cells. T3S depends on HrpB2, which is a component of the predicted periplasmic inner rod structure of the secretion apparatus. HrpB2 is secreted during the early stages of the secretion process and interacts with the cytoplasmic domain of the inner membrane protein HrcU. Here, we localized the secretion and translocation signal of HrpB2 in the N-terminal 40 amino acids and show that this region is sufficient for the interaction with the cytoplasmic domain of HrcU. Our results suggest that the T3S signal of HrpB2 is required for the docking of HrpB2 to the secretion apparatus. Furthermore, we provide experimental evidence that the N-terminal region of HrpB2 is sufficient to target effector proteins for translocation in a nonpathogenic X. campestris pv. vesicatoria strain.
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Affiliation(s)
- Felix Scheibner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Steve Schulz
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Jens Hausner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | | | - Daniela Büttner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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Salinas SR, Petruk AA, Brukman NG, Bianco MI, Jacobs M, Marti MA, Ielpi L. Binding of the substrate UDP-glucuronic acid induces conformational changes in the xanthan gum glucuronosyltransferase. Protein Eng Des Sel 2016; 29:197-207. [PMID: 27099353 DOI: 10.1093/protein/gzw007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 03/02/2016] [Indexed: 01/24/2023] Open
Abstract
GumK is a membrane-associated glucuronosyltransferase of Xanthomonas campestris that is involved in xanthan gum biosynthesis. GumK belongs to the inverting GT-B superfamily and catalyzes the transfer of a glucuronic acid (GlcA) residue from uridine diphosphate (UDP)-GlcA (UDP-GlcA) to a lipid-PP-trisaccharide embedded in the membrane of the bacteria. The structure of GumK was previously described in its apo- and UDP-bound forms, with no significant conformational differences being observed. Here, we study the behavior of GumK toward its donor substrate UDP-GlcA. Turbidity measurements revealed that the interaction of GumK with UDP-GlcA produces aggregation of protein molecules under specific conditions. Moreover, limited proteolysis assays demonstrated protection of enzymatic digestion when UDP-GlcA is present, and this protection is promoted by substrate binding. Circular dichroism spectroscopy also revealed changes in the GumK tertiary structure after UDP-GlcA addition. According to the obtained emission fluorescence results, we suggest the possibility of exposure of hydrophobic residues upon UDP-GlcA binding. We present in silico-built models of GumK complexed with UDP-GlcA as well as its analogs UDP-glucose and UDP-galacturonic acid. Through molecular dynamics simulations, we also show that a relative movement between the domains appears to be specific and to be triggered by UDP-GlcA. The results presented here strongly suggest that GumK undergoes a conformational change upon donor substrate binding, likely bringing the two Rossmann fold domains closer together and triggering a change in the N-terminal domain, with consequent generation of the acceptor substrate binding site.
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Affiliation(s)
- S R Salinas
- Laboratory of Bacterial Genetics, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - A A Petruk
- Departamento de Química Inorgánica, Analítica, y Química Física/INQUIMAE CONICET, Córdoba, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - N G Brukman
- Laboratory of Bacterial Genetics, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - M I Bianco
- Laboratory of Bacterial Genetics, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - M Jacobs
- Laboratory of Bacterial Genetics, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - M A Marti
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - L Ielpi
- Laboratory of Bacterial Genetics, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
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Buchko GW, Perkins A, Parsonage D, Poole LB, Karplus PA. Backbone chemical shift assignments for Xanthomonas campestris peroxiredoxin Q in the reduced and oxidized states: a dramatic change in backbone dynamics. Biomol NMR Assign 2016; 10:57-61. [PMID: 26438558 PMCID: PMC4789116 DOI: 10.1007/s12104-015-9637-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 09/09/2015] [Indexed: 05/11/2023]
Abstract
Peroxiredoxins (Prx) are ubiquitous enzymes that reduce peroxides as part of antioxidant defenses and redox signaling. While Prx catalytic activity and sensitivity to hyperoxidative inactivation depend on their dynamic properties, there are few examples where their dynamics has been characterized by NMR spectroscopy. Here, we provide a foundation for studies of the solution properties of peroxiredoxin Q from the plant pathogen Xanthomonas campestris (XcPrxQ) by assigning the observable (1)H(N), (15)N, (13)C(α), (13)C(β), and (13)C' chemical shifts for both the reduced (dithiol) and oxidized (disulfide) states. In the reduced state, most of the backbone amide resonances (149/152, 98 %) can be assigned in the XcPrxQ (1)H-(15)N HSQC spectrum. In contrast, a remarkable 51 % (77) of these amide resonances are not visible in the (1)H-(15)N HSQC spectrum of the disulfide state of the enzyme, indicating a substantial change in backbone dynamics associated with the formation of an intramolecular C48-C84 disulfide bond.
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Affiliation(s)
- Garry W Buchko
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Arden Perkins
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, 97331, USA
| | - Derek Parsonage
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - P Andrew Karplus
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, 97331, USA.
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Barua R, Alam MJ, Salim M, Ashrafee TS. Small scale production and characterization of xanthan gum synthesized by local isolates of Xanthomonas campestris. Indian J Exp Biol 2016; 54:151-155. [PMID: 26934783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Xanthan gum is a commercially important microbial exopolysaccharide (EPS) produced by Xanthomonas campestris. X. campestris is a plant pathogen causing various plant diseases such as black rot of crucifers, bacterial leaf blight and citrus canker disease resulting in crop damage. In this study, we isolated efficient local bacterial isolates which are capable to produce xanthan gum utilizing different sources of carbon (maltose, sucrose and glucose). Bacterial isolates from different plant leaves and fruits were identified as Xanthomonas campestris based on their morphological and biochemical characteristics. Among the 23 isolates, 70% were capable of producing gum. Taro plant, considered as new bacterial host, also have the capability to produce xanthan gum. Production conditions of xanthan gum and their relative viscosity by these bacterial isolates were optimized using basal medium containing commercial carbon and nitrogen sources and various temperature and rotation. Highest level of xanthan gum (18.286 g/l) with relative viscosity (7.2) was produced (Host, Citrus macroptera) at 28 degrees C, pH 7.0, 150 rpm using sucrose as a carbon source at orbital shaker. Whereas, in lab fermenter, same conditions gave best result (19.587 g/l gum) with 7.8 relative viscosity. Chilled alcohol (96%) was used to recover the xanthan gum. FTIR studies also carried out for further confirmation of compatibility by detecting the chemical groups.
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Luvielmo MDM, Borges CD, Toyama DDO, Vendruscolo CT, Scamparini ARP. Structure of xanthan gum and cell ultrastructure at different times of alkali stress. Braz J Microbiol 2016; 47:102-9. [PMID: 26887232 PMCID: PMC4822773 DOI: 10.1016/j.bjm.2015.11.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/29/2015] [Indexed: 11/20/2022] Open
Abstract
The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress.
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Affiliation(s)
| | | | - Daniela de Oliveira Toyama
- Department of Food Sciences, Faculdade de Engenharia de Alimentos, Universidade Estadual de Campinas, SP, Brazil
| | - Claire Tondo Vendruscolo
- Center of Technological Development, Biopolymeres, Universidade Federal de Pelotas, Pelotas, RS, Brazil
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Kakkar A, Nizampatnam NR, Kondreddy A, Pradhan BB, Chatterjee S. Xanthomonas campestris cell-cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan. J Exp Bot 2015; 66:6697-714. [PMID: 26248667 PMCID: PMC4623683 DOI: 10.1093/jxb/erv377] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell-cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell-cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery.
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Affiliation(s)
- Akanksha Kakkar
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India Graduate studies, Manipal University, Manipal, India
| | | | - Anil Kondreddy
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Binod Bihari Pradhan
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Subhadeep Chatterjee
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
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